“Secrets of Selfridges” (8 p.m., PBS): This compelling special takes viewers to the department store in London where luxury shopping was born.

“JFK: The Smoking Gun” (8 p.m., Reelz): Brace yourself for a deluge of programs pegged to the 50th anniversary of President John F. Kennedy’s assassination. Tonight brings this documentary asserting new evidence about who “really” killed Kennedy.

“The Walking Dead” (9 p.m., AMC): Rick deals with the fallout from Carol’s shocking confession last week. Can the group ever be the same?

“Masters of Sex” (10 p.m., Showtime): The drama continues as Bill and Libby Masters (Michael Sheen and Caitlin FitzGerald) head to Miami for a break after their crushing miscarriage. However, Bill is drawn back to his work by a sexually adventurous couple next door.

DirecTV Now has some attractive features, including its price, but the overall service is disappointing and an inadequate substitute for a traditional pay TV package, Tech Files columnist Troy Wolverton says.